Seroprevalence of leptospirosis in man and animals in Tamilnadu.

Leptospirosis, is a worldwide zoonosis caused by from various parts of Chennai received between 1997 and 2006 spirochetes of the genus Leptospira affecting humans and showed 57.55% seropositivity. Samples received between April animals; humans are incidental hosts. Ayyar made the earliest 2003 and March 2006 (N= 25, 449) were used to study the record of leptospirosis in Tamil Nadu among Madras hounds. distribution of serogroups and prevalence trend studies, while Subsequently, Venkataraman and Jaganathan reported the samples from October 2004 to December 2004 were used to occurrence of an outbreak of leptospirosis in Madras state. study the disease-distribution with reference to sex and age. Following this, a survey on the incidence of leptospirosis Serum samples from apparently healthy human subjects among domestic animals in and around Madras City belonging to two risk groups were screened. Group 1 (presently Chennai) was made by Jawad Hussain. Since then comprised of 37 veterinary doctors and 76 supportive staff reports on isolation of leptospires, seroprevalence among from Cuddalore district, a coastal area south of Chennai and and in human beings were made from Tamil Group 2 comprised of 151 conservancy workers in Coimbatore Nadu. However, most of the literature on leptospirosis is district, located in the western border of Tamil Nadu. repetitive in nature. Serum samples from domesticated animals (671 cattle, 219 Faine et al observed that prevention measures included buffaloes, 151 sheep, 144 goats, 62 pigs, 241 dogs, 1 cat and a knowledge on the number and frequency of both human or 4 horses), wild animals in captivity (8 elephants, 5 lions, 2 each animal cases, the infecting serovar, serogroup or genetic group jackal and bonnet macaque, one each long tailed macaque, of leptospires, their maintenance host, means of transmission spotted deer and barking deer, panther and 27 rodents-Rattus and the prevalence of antibodies indicating subclinical rattus) were analyzed. infection in the population. Seroprevalence analysis Here, we furnish data on the percent positivity to leptospirosis in blood serum tested since 1997. Detailed Overall seropositivity by MAT in human samples was analysis has been done on the serogroup distribution in the found to be 57.55%; highest (78.70%) during 1998-1999 and past three years (April 2003 to March 2006), percent positivity lowest (32.82%) in 2002-2003. Number of specimens received and serogroup distribution among different sexes and age increased from 2054 in 1997-1998 to 10, 014 in 2005-2006. This group of clinically suspected human patients in Chennai reflected on the increased awareness about the disease. (October 2004 to December 2005) and apparently healthy Analysis of the 25, 449 serum samples received between individuals belonging to risk groups (veterinary professionals April 2003 and March 2006 showed that the seropositivity and conservancy workers). Seroprevalence in various animal during the three years was found to be 43.16%, 60.89% and species screened in Tamil Nadu during (April 2004 and March 67.62% respectively. The seropositivity during 2003 2004 was 2006) are also furnished. less when compared to the subsequent years, which may be Serum samples (human and animal) and screening by due to failure in monsoon and the increase in 2004-2005 and microscopic agglutination test (MAT) 2005-2006 may be due to the Tsunami and heavy floods in Tamil Nadu. Screening of human and animal serum samples was animals